SITE OF MYOCARDIAL-ISCHEMIA AS A DETERMINANT OF POSTEXERCISE BLOOD-PRESSURE AND HEART-RATE RESPONSE IN CORONARY-ARTERY DISEASE

Forty patients with coronary artery disease and 15 normal subjects (gr oup C) were studied to assess the influence of the site of stress-indu ced myocardial ischemia on cardiovascular response after exercise. Pat ients were divided in 2 groups according to myocardial thallium-201 sc intigraphy: those with an anteroseptal reversible perfusion defect (gr oup A; n = 24), and those with an inferoposterior reversible perfusion defect (group I; n = 16). All patients underwent serial bicycle exerc ise stress tests. The first 2 stress tests were interrupted when 0.1 m V of ST-segment depression was achieved (2,000 to 2,500 kg-m); a third test was stopped before the onset of ischemia (1,500 kg-m). Normal su bjects performed stress tests at comparable work loads. At ischemic th reshold, there was no difference in ejection fraction between groups A (65.5%) and I (67.3%). Mean values and recovery ratios of heart rate and systolic blood pressure were significantly higher in group A than in C and I during the recovery period of the 2,000 to 2,500 kg-m stres s test. In contrast, no significant difference was observed among the groups in the 1,500 kg-m stress test, and between groups I and C in an y stress test. The data show that in patients with the same degree of stress-induced impairment of ventricular function, the anterior site o f ischemia leads to persistently higher values of heart rate and blood pressure after exercise, which are likely due to an enhanced adrenerg ic discharge.